Sun Safety

Stay indoors or look for shade in the middle of the day when UV radiation is strongest, usually between 10am and 4pm.

Seek shade under an umbrella, tree, or other shelter before you need relief from the sun.

Plan outdoor activities for the early morning or late afternoon, when UV radiation is typically one third of what it is at midday.

Cover up – long-sleeved shirts, long pants, wide-brimmed hats, and sunglasses offer the best protection against UV radiation.

If you can’t cover up completely, be sure to use a broad-spectrum sunscreen with a sun protection factor (SPF) of at least 30 on all exposed skin.

What about Vitamin D?

But don’t I need some sun – especially to make vitamin D?

It’s true that vitamin D is important for health; that many of us are deficient, and sunlight is one way to help your body make vitamin D. However, because of the risks associated with UV radiation, the National Institute of Health, recommends that you focus on getting vitamin D from food or supplements rather than the sun.

American Cancer Society Sun Protection Message

Slip! Slop! Slap! Wrap!

To help you remember some of the basic sun safety tips, the American Cancer Society has adopted this simple message created in Australia: Slip! Slop! Slap! Wrap!

SLIP on a shirt. Clothing is one the most effective protections against UV radiation. Keep the following tips in mind:

Long-sleeved shirts and long pants offer the best protection.

A tight weave, such as the cotton knit of a t-shirt, offers more protection than a loose weave. For a rough idea of a fabric’s ability to block UV rays, hold it up to the light. Fabrics that allow more light to come through will probably let more UV radiation through as well.

Dark colors are more absorbent and less reflective than light colors and so offer better protection.

Dry clothing is more protective than wet. A wet t-shirt offers protection equivalent to about an SPF of only 4.

SLOP on sunscreen. Sunscreens absorb, reflect, or scatter most but not all UV rays before they can penetrate the skin. Look for sunscreens with the following features:

A sun protection factor (SPF) of at least 30. SPF measures how long a product protects the skin from UVB rays before it starts to burn, compared with how long it takes to burn without protection. If you start to burn in 10 minutes without protection, using an SPF 15 sunscreen theoretically will prevent you from burning 15 times longer, or about 2.5 hours. An SPF of 15 blocks 93% of UVB rays. SPFs of 30 and higher block 97% of UVB rays and are suggested for people who are sun-sensitive, have skin cancer, or are at a high risk for developing skin cancer.

Make sure you put on an adequate amount of sunscreen and reapply every 2 to 3 hours and more regularly if you are swimming. The number one cause of people sunburning even when they have sunscreen on is a failure to reapply it after several hours.

A “waterproof” feature, if you will be sweating or swimming.

A valid expiration date. Sunscreen without an expiration date has a shelf life of no more than 3 years. Some sunscreen ingredients can degrade and lose their effectiveness over time, particularly when exposed to extreme temperatures.

SLAP on a hat. For the most protection, wear a hat with a brim wide enough to shade your face, ears, and the back of your neck. Look for hats made of tightly woven fabrics, such as canvas. Avoid loose weaves, particularly straw hats with holes that allow sunlight through. If you prefer to wear a baseball cap, make sure to protect your ears and the back of your neck. Wear clothing that covers those areas, use sunscreen with at least SPF 30, or stay in the shade.

WRAP on sunglasses. Sunglasses protect your eyes, your eyelids, and the delicate skin around your eyes from UV rays. They also reduce the risk of cataracts.

The American National Standards Institute (ANSI) requires that sunglasses block a minimum of 50% of UVA and 70% of UVB rays. Glasses labeled “meets ANSI requirements” or “UV absorption up to 400 nm” provide 99% to 100% protection from UVA and UVB rays. Glasses labeled “cosmetic” block 70%. Avoid buying sunglasses that carry no label.

Darker sunglasses or polarized lenses don’t necessarily offer more UV protection. UV protection is provided by a chemical that makes up part of the invisible coating on the lenses, regardless of how dark they are.

Wraparound sunglasses prevent UV rays from entering your eyes from the sides.
Don’t buy “toy sunglasses” for your children. Look for the same UV protection in children’s sunglasses as you would in adult glasses.

About Sunscreens

What Is Sunscreen SPF?

SPF is the abbreviation for Sun Protection Factor and is the system used worldwide to determine how much protection a sunscreen provides, applied to the skin at a thickness of 2 mg/cm2. This system calculates how much UV radiation (mostly UVB) it takes to cause a barely detectable sunburn on a given person with and without sunscreen applied. For example, if it takes 10 minutes to burn without a sunscreen and 100 minutes to burn with a sunscreen, then the SPF of that sunscreen is 10 (100/10).

Currently there is no internationally agreed-upon test for measuring UVA protection in human skin. An estimate is made by a laboratory test in which the proportion of radiation passing through a measured amount of sunscreen is determined. To ensure some protection against UVA, products with physical blocking agents making up some of the active ingredients are recommended.

Two Classes of Sunscreen

Sunscreens can be broadly classified into 2 groups: chemical absorbers and physical blockers.

Chemical absorbers work by absorbing ultraviolet (UV) radiation and can be further differentiated by the type of radiation they absorb, UVA or UVB, or both UVA and UVB.

Physical blockers work by reflecting or scattering the UV radiation.

Chemical Absorbers

The table below is a list of some of the common chemical absorbers available and the protection they provide against the UV range.

Aminobenzoic acid derivatives

Chemical

UVB (290-320nm)

UVA II (320-340nm)

UVA I (340-400nm)

PABA

Partial

None

None

Glyceryl PABA

Partial

None

None

Padimate O

Partial

None

None

Roxadimate

Complete

Partial

None

Benzotriazoles

Chemical

UVB (290-320nm)

UVA II (320-340nm)

UVA I (340-400nm)

Medroxyl

Partial

None

Partial

Benzophenones

Chemical

UVB (290-320nm)

UVA II (320-340nm)

UVA I (340-400nm)

Dioxybenzone

Complete

Complete

Partial

Avobenzone

Complete

Complete

Partial

Oxybenzone

Complete

Complete

Partial

Sulisonbenzone

Complete

Complete

Partial

Cinnamates

Chemical

UVB (290-320nm)

UVA II (320-340nm)

UVA I (340-400nm)

Octocrylene

Complete

Complete

Partial

Octyl methoxycinnamate

Complete

None

None

Salicylates

Chemical

UVB (290-320nm)

UVA II (320-340nm)

UVA I (340-400nm)

Homosalate

Partial

None

None

Ethylhexyl salicylate

Complete

None

None

Trolamine salicylate

Complete

None

None

Chemical absorbing sunscreens often contain a combination of ingredients to get coverage against both UVB and UVA radiation. Some are also combined with physical blockers.

Some organic formulations may degrade when exposed to sunlight; they may therefore not perform as well as expected.

Physical Blockers

Physical blockers are effective at protecting against both UVA and UVB radiation. The 2 most common physical blockers are titanium dioxide and zinc oxide.